Det.-Sgt. Terry Browne says an armed security guard, who was apparently in the restaurant to buy food, discharged his weapon following a "significant physical altercation" with two men.
Browne says the altercation took place somewhere near the food counter and there were between 15 and 20 customers and staff in the McDonald's at the time of the incident.
Police say the two unidentified men, believed to be aged 25 and 40, were pronounced dead at the scene, while the security guard was taken to hospital for treatment of a hand injury.
Browne says the guard, who was employed nearby, is co-operating with investigators.
Browne says police are not looking for any suspects and says the reason for the confrontation isn't yet known but investigators are going through security video of the incident.
"I can't tell you why it started. From what I see on the video, it started very quickly and escalated from there," he told a news conference Saturday morning.
"There's no doubt that the security guard is the involved party for the discharging of the firearm, we're really trying to put the pieces together on how this all played out," Browne said.
Browne added that no one is under arrest at this point.
"We know where the individual is, he's being co-operative and we'll take it step-by-step," he said.
Police say no one else in the restaurant was injured.
There were "six to eight" employees and "10 to 12" customers in the area when "multiple shots" were fired before 3 a.m., Browne said.
Browne did not say exactly where the confrontation occurred, but said it was in the "general area where customers line up for food," and wouldn't say if other weapons were involved.
Browne stressed that the investigation was in the early stages, but said the video shows "fairly significant physical confrontation ... and the security guard was involved in this confrontation."
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